The aim of the study was to determine the allelopathic effect of (Ruta graveolens L.) on germination and early growth of weed species hoary cress (Lepidium draba (L.) Desv.) under laboratory conditions. Cogermination of hoary cress with rue seeds, water extracts from fresh and dry rue biomass in concentrations of 5 and 10% were evaluated in Petri dishes. Effect of water extracts from fresh rue biomass in 5 and 10% concentrations as well as effects of fresh and dry rue plant residues in two rates (10 and 20 g/kg of soil) were examined in pots with soil. Seed cogermination showed negative effects on weed seed germination which was reduced by 24.2%. The Petri dishes, water extracts from fresh and dry rue biomass had inhibitory effect on the germination and growth of weeds, especially extracts from dry biomass up to 100%. Extracts from fresh biomass had a lower negative effect. In pots with soil extracts from fresh rue biomass had no significant effect on the studied parameters. Extracts had lower impact in pots with soil. Fresh rue residues incorporated into the soil reduced germination on average by 30.9%. Fresh seedlings weight was stimulated in treatments with dry residues.